Joist noise reduction system and method of installation

ABSTRACT

A noise reducing joist system includes a joist hanger, a joist and a sheath surrounding a bottom portion, a lower end portion and lower end side portions of the joist, the sheath and joist inserted into the joist hanger. The joist and sheath are inserted into the joist hanger. The sheath interfaces with the joist hanger rather than the joist thereby reducing noise that may be created by a sliding that might occur between the joist end the joist hanger.

TECHNICAL FIELD

This disclosure relates to structural joist systems and more particularly to reducing noise in structural joist systems at the joist-joist hanger interface.

BACKGROUND

One source of squeaky floors is a poor connection between a floor joist and a joist hanger. If the joist is improperly fit into the joist hanger, the fit between the two may loosen up over time and use causing the joist to rub up and down against the joist hanger when loads are applied, thereby causing a squeak.

Currently, composite I-beam joist manufacturers recommend applying an adhesive to the joist hanger before inserting the joist. While the manufacturers recommend using the adhesive sparingly, in reality, construction workers tend to apply more adhesive. FIG. 1 shows composite I-beam joist 20 inserted into joist hanger 22 with the adhesive 24 depicted as oozing up and over the bottom flange 26 of the joist 20. This tendency to over-apply the adhesive may be due to a desire to make sure enough adhesive will hold the joist in the hanger over a long period of time. This need to hold the joist in the hanger is important because many “squeak-free” floor systems come with an extended warranty against any future squeaks.

The adhesive is messy, smelly, and depending on the type of adhesive used, highly flammable. Also, adhesives will out-gas chemicals over a period of time that may last until well after the floor is installed. Further, if repairs are needed to be made for any reason at the joist hanger interface, the adhesive must be painstakingly chipped away and the joist and joist hanger may even need to be completely scrapped.

SUMMARY OF THE DISCLOSURE

A noise reducing joist system includes a joist hanger, a joist and a sheath surrounding a bottom portion, a lower end portion and lower end side portions of the joist, the sheath and joist inserted into the joist hanger. The joist and sheath are inserted into the joist hanger.

The system is installed by a method where the joist hanger is installed and the sheath is fitted onto the joist to surround over a bottom portion, a lower end portion and lower end side portions of the joist. The joist and sheath are then inserted into the joist hanger.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a current joist hanging system showing adhesive applied to the joist.

FIG. 2 is a perspective view of a joist hanging system.

FIG. 3 is a cross-sectional view of the joist hanging system of FIG. 2 taken along line 3-3 in FIG. 2.

FIG. 4 is a cross-sectional view of the joist hanging system of FIG. 2 taken along line 4-4 in FIG. 2.

DETAILED DESCRIPTION

Instead of using adhesive to ensure a fixed, tight fit between a joist and a joist hanger, this disclosure describes using a plastic sheath fit over the bottom end of the joist and interposed between the joist and the joist hanger. Rather than trying to achieve a permanent fit, the plastic sheath allows for the expected loosening of the interface between the joist and joist hanger due to repeated loading. Any loosening now results in a sliding between the joist and the plastic sheath or between the sheath and the joist hanger which produces far less noise than a sliding between the joist and the joist hanger. Further, the sheath allows for easy removal in case any repairs must be made at the joist hanger without needing to remove adhesive or scrap the joist or joist hanger.

FIG. 2 is a perspective view of the joist hanging system 30. A bottom portion 32, lower end portion 34 shown in FIG. 3 and lower end side portions 36 of a joist 38 are surrounded by a removable sheath 40. The sheath 40 and joist 38 are inserted into the joist hanger 42.

The sheath 40 may be made from a plastic, though other materials that provide a quiet sliding interface may also be used to make the sheath. When the sheath 40 is made from plastic, it may be made from an injection molded plastic and/or fire resistant plastic.

The joist 38 is shown in FIG. 2 as being a composite I-beam joist typically used in squeak-free flooring applications. The system 30, however, may be used with other types of joists that utilize joist hangers.

FIG. 3 is a cross-sectional view of a portion of the joist hanging system 30 taken along line 3-3 in FIG. 2. The sheath 40 is rectangular in shape with an interior portion that is sized to receive the bottom flange 44 of the composite I-beam joist 38. The sheath covers a height 46 of the bottom flange 44 along the end side portions and the end of the bottom flange 44. Covering the bottom flange along this areas ensures the only the sheath 40 will interface with the joist hanger. To make sure the bottom flange 44 is covered by the sheath 40, the sheath 40 may extend above the height 46 of the bottom flange 38.

FIG. 4 is a cross-sectional view of a portion of the joist hanging system 30 taken along line 4-4 in FIG. 2. The removable sheath 40 has an interior width 48 and the bottom flange 38 has a width 50. The interior width 48 of the sheath 40 may be less than the width 50 of the bottom flange 38 to form an interference fit between the sheath 40 and the bottom flange 38. The interior width 48 may be around 0.08 inches less than the bottom flange width 50.

The joist hanger 42 is sized to have an interior width 52 to snugly receive the outer width 54 of the sheath 40.

FIGS. 2-4 will now be used to help describe a method of installing a noise reducing joist system 30. The joist hanger 42 is installed at a required location. The sheath 40 is placed over the bottom corner of the joist 38 so that the bottom portion 32, lower end portion 34 and lower end side portions 36 are surrounded by the sheath 40. The joist 38 and sheath 40 are then inserted into the joist hanger 42.

The joist 38 may be a composite I-beam joist typically used in “squeak-free” flooring systems with the sheath 40 surrounding the bottom portion 32, end portion 34 and side portions 36 of the bottom flange 44. Surrounding the bottom flange 44 may include covering a height 46 of the bottom flange 44.

Surrounding the bottom flange 44 with the sheath 40 may include fitting the sheath 40 over the end portion of the bottom flange 44 with an interference fit.

Installing the joist hanger 42 may include installing a joist hanger that is sized to snugly receive an outer width 54 of the sheath 40. 

1. A noise reducing joist system comprising: a joist; a joist hanger; and a removable sheath surrounding a bottom portion, a lower end portion and lower end side portions of the joist, the sheath and joist inserted into the joist hanger.
 2. The system of claim 1, wherein the removable sheath is comprised of a plastic.
 3. The system of claim 2, wherein the removable sheath is comprised of an injection molded plastic.
 4. The system of claim 2, wherein the removable sheath is comprised of a fire-resistant plastic.
 5. The system of claim 1, wherein the joist is a composite I-beam.
 6. The system of claim 5, wherein the removable sheath covers a height of a bottom flange of the composite I-beam along end side portions of the bottom flange and an end of the bottom flange.
 7. The system of claim 6, wherein the removable sheath extends above the height of the bottom flange of the composite I-beam.
 8. The system of claim 5, wherein an interior width of the removable sheath has a width less than a width of a bottom flange of the composite I-beam to form an interference fit between the removable sheath and the bottom flange of the composite I-beam.
 9. The system of claim 1, wherein an opening in the joist hanger is sized to snugly receive an outer width of the sheath.
 10. A method of installing a noise reducing joist system comprising: installing a joist hanger; surrounding a bottom portion, a lower end portion and lower end side portions of a joist with a sheath; inserting the joist and sheath into the joist hanger.
 11. The method of claim 10, wherein surrounding a bottom portion, a lower end portion and lower end side portions of a joist with a sheath includes surrounding a bottom portion, a lower end portion and lower end side portions of a joist with a plastic sheath.
 12. The method of claim 11, wherein surrounding a bottom portion, a lower end portion and lower end side portions of a joist with a plastic sheath includes surrounding a bottom portion, a lower end portion and lower end side portions of a joist with a fire-resistant plastic sheath.
 13. The method of claim 10, wherein surrounding a bottom portion, a lower end portion and lower end side portions of a joist with a sheath includes surrounding a bottom portion, a lower end portion and lower end side portions of a composite I-beam joist with a sheath.
 14. The method of claim 13, wherein surrounding a bottom portion, a lower end portion and lower end side portions of a composite I-beam joist with a sheath includes covering a height of a bottom flange of the composite I-beam long end side portions of the bottom flange and an end of the bottom flange.
 15. The method of claim 13, wherein surrounding a bottom portion, a lower end portion and lower end side portions of a composite I-beam joist with a sheath includes fitting the sheath over an end portion of a bottom flange of the composite I-beam with an interference fit.
 16. The method of claim 13, wherein installing a joist hanger includes installing a joist hanger sized to snugly receive an outer width of the sheath. 